Root Cause Failure Analysis of Printed Circuit Board ... - SMTA

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Effect of Lead Length on Topside Fillet Formation 1.0mm Φ hole, 0.45mm Φ lead Lead Length: 0.040”/1mm Lead Length: 0.080”/2mm Lead Length: 0.120”/3mm • Lead Length protrusion too long on solder side: – Only a small quantity of solder retained in soldering area, solder flow downwards along component lead • Lead Length protrusion too short on solder side: – Only a small quantity of solder can transferred, and the heat transfer maybe insufficient
Solder Mask Selection Matte Finish Solder Mask Has Increase Surface Energy To Hold Flux To The Board (More Flux For Solder Joint Formation) Dull/Low Reflection Appearance Glossy Finish Solder Mask Has Low Surface Energy to Flux To The Board (Less Flux For Solder Joint Formation – Solder Balls, Icicles, Flags, etc.) Highly Reflective Appearance Preferred Preferred Not Not Preferred Preferred
Page 1 and 2: Root Root Root Cause Cause Failure
Page 3 and 4: Today’s Electronic Designs • Co
Page 5 and 6: Component Issues - Warpage • High
Page 7 and 8: Component Issues - Decreasing Pitch
Page 9 and 10: LGA Pad Design Solder Solder Mask M
Page 11 and 12: % PAD SIZE INCREASE 60 50 40 30 20
Page 13 and 14: Component Pad - Thermal Imbalance
Page 15 and 16: Thick Copper Design A A CTE CTE Mis
Page 17 and 18: Thick Copper Design Lack Lack Of Of
Page 19 and 20: Copper Etch Process • H H = = = H
Page 21 and 22: Pad Size Reduction Current Procedur
Page 23 and 24: • Voids in Solder Joints - Unfill
Page 25 and 26: Stencil Tolerances Artwork Artwork
Page 27 and 28: Offset Paste - Normal Placement Pho
Page 29 and 30: Match Placement To Paste • Slight
Page 31 and 32: Solder Paste Printing Volume Air Bu
Page 33 and 34: Internal PCB Impacts Number Of Laye
Page 35 and 36: Wave Solder & Rework Issues 0.005
Page 37 and 38: PCB Finish Vs Solder Spread - OSP -
Page 39 and 40: Defects Caused By Improper Thermal
Page 41 and 42: Through Hole Pad Design • Square
Page 43: Effect of Board Thickness On Topsid
Page 47 and 48: Cleaning Chemistry Compatibility
Page 49 and 50: Inspectability - AOI, AXI, HVI •
Page 51 and 52: Cracked Cap Issue • PCA Is Assemb
Page 53 and 54: Source Of Contamination What is Sou
Page 55 and 56: DFX Software Flexibility • Concur
Page 57 and 58: DFX PCA-PCB Software Systems Mentor
Page 59 and 60: DFX Mechanical Software Systems Ana
Page 61 and 62: Closing Thought “We can’t solve

Root Cause Failure Analysis of Printed Circuit Board ... - SMTA

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